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[6] DT for heat pump domestic water heating mode
Applies only to installations with a domestic hot water tank.
The 'DT (temperature difference) for heat pump domestic water
heating mode' field settings determine the temperatures at which
heating of the domestic hot water by the heat pump will be started
(i.e., the heat pump ON temperature) and stopped (i.e., the heat
pump OFF temperature).
When the domestic hot water temperature drops below the heat
pump ON temperature (
T
HP ON
the heat pump will be started. As soon as the domestic hot water
temperature reaches the heat pump OFF temperature (
the user set point temperature (
by the heat pump will be stopped (by switching the 3-way valve).
The heat pump OFF temperature, and the heat pump ON
temperature, and its relation with field settings [6-00] and [6-01] are
explained in the illustration below.
[6-00] Start: temperature difference determining the heat
pump ON temperature (
[6-01] Stop: temperature difference determining the heat
pump OFF temperature (
T
> T
U
HP MAX
T
= 70°C
U
T(°C)
[6-01] =
2°C
[6-00] =
7°C
70
T
U
50
T
[6-01]
HP MAX
48
T
HP OFF
[6-00]
41
T
HP ON
T
User set point temperature (as set on the user interface)
U
T
Maximum heat pump temperature at sensor in domestic hot
HP MAX
water tank (50°C)(depending on T
T
Heat pump OFF temperature
HP OFF
T
Heat pump ON temperature
HP ON
≤25°C.
(a) 50°C = T
at T
HP MAX
A
48°C = T
at T
>25°C.
HP MAX
A
The maximum domestic hot water temperature that can be
reached with the heat pump is 50°C. It is advised to select
T
not higher than 48°C in order to improve
HP OFF
performance of the heat pump during domestic water
heating mode.
When setting [4-03]=0 or 2 special attention to setting
[6-00] is recommended. A good balance between the
required domestic hot water temperature and heat pump
ON temperature (T
HP ON
EKHBH/X016BA
Indoor unit for air to water heat pump system
4PW54187-1B
), heating of the domestic hot water by
T
HP OFF
), heating of the domestic hot water
T
U
). See illustration.
T
HP ON
). See illustration.
T
HP OFF
T
< T
U
HP MAX
T
= 45°C
U
T(°C)
[6-01] =
[6-00] =
50
T
HP MAX
45
T
= T
U
HP OFF
[6-00]
38
T
HP ON
(a)
)
A
) is a must.
[7] DT for booster heater and dual set point control
DT for booster heater
Applies only to installations with a domestic hot water tank.
When the domestic hot water is heated and the domestic hot water
set point temperature (as set by the user) has been reached, the
booster heater will continue to heat the domestic hot water to a
temperature a few degrees above the set point temperature, i.e. the
booster heater OFF temperature. These extra degrees are specified
by the domestic hot water step length field setting. Correct setting
prevents the booster heater from repeatedly turning on and off (i.e.
) or
chattering) to maintain the domestic hot water set point temperature.
Note: the booster heater will turn back on when the domestic hot
water temperature drops [7-01] (field setting) below the booster
heater OFF temperature.
If the schedule timer for booster heater (see the operation
manual) is active, the booster heater will only operate if
allowed by this schedule timer.
[7-00] Domestic
difference above the domestic hot water set point
temperature before the booster heater is turned off.
T
DHW
T
73
BH OFF
2°C
T
71
BH ON
7°C
T
70
U
60
T
50
HP MAX
T
48
HP OFF
T
41
HP ON
40
30
20
10
5
BH
HP
T
BH OFF
T
BH ON
T
HP MAX
T
HP OFF
T
HP ON
T
DHW
T
U
t
WARNING
Be aware that the domestic hot water temperature will be
automatically increased (always) with the value selected in
field setting [7-00] compare to the user set point for
domestic hot water (T
the operation manual to select preferable set point.
If this high water temperature can be a potential risk for
human injuries, a mixing valve (field supply) shall be
installed at the hot water outlet connection of the domestic
hot water tank. This mixing valve shall secure that the hot
water temperature at the hot water tap never rise above a
set maximum value. This maximum allowable hot water
temperature shall be selected according to local and
national regulations.
If the booster heater operation is limited ([4-03]=0), then
set point of field setting parameter [7-00] has only meaning
for powerful domestic water heating.
hot
water
step
[7-00]
[6-01]
[6-00]
T
[7-00] =
HP
BH
[6-01] =
[6-00] =
Booster heater
Heat pump. If heating up time by the heat pump takes too
long, auxiliary heating by the booster heater can take place
Booster heater OFF temperature (T
Booster heater ON temperature (T
Maximum heat pump temperature at sensor in domestic hot
water tank
Heat pump OFF temperature (T
HP MAX
Heat pump ON temperature (T
HP OFF
Domestic hot water temperature
User set point temperature (as set on the user interface)
Time
). Refer to field setting [7-00] and
U
length:
temperature
[7-01]
= 70°C
U
3°C
HP
2°C
7°C
t
+ [7-00])
U
– [7-01])
BH OFF
– [6-01])
– [6-00])
Installation manual
27
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